Type I Error

In hypothesis testing, rejecting the null hypothesis (no difference) when it is in fact true (e.g. convicting an innocent person.)

TYPE 1 errors are those where scientists assumed a relationship where none existed. The Producers risk: Rejecting a good part.

When a point falls out of the boundary limit and the SPC system gives signal that the process is out of control or produced product is bad in Quality but actually nothing have gone wrong (i.e., the process is in control).